Coordinate data entry device
US6788296B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 2002 |
| Grant date | Sep 7, 2004 |
| Priority date | — |
| Expiry date | Apr 16, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/043
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention provides a coordinate data entry device comprising a plurality of receivers disposed in the vicinity of a board surface, and a position indicator to transmit signals, at least one of which employs ultrasonic waves, to the receivers, thereby detecting the position of the position indicator on the board surface and making the coordinate position thereof available for entry, in which the signal employing ultrasonic waves is transmitted at an arbitrary time interval, and an ultrasonic oscillating circuit transmitting the signal employing ultrasonic waves comprises a resonant circuit formed of an ultrasonic resonator and a coil, which are connected in parallel with each other, and the amplitude of a start current of the ultrasonic resonant circuit is made variable according to the lapse of time, thus allowing the variations in performance of the resonant circuit including the ultrasonic resonator to be smoothed out and making stabilized positional detection possible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.